The present invention relates to a golf ball having a core and one or more cover layer molded over the core. More specifically, the invention relates to a golf ball which undergoes little change in ball weight and little change in initial velocity due to the absorption of moisture and the like.
It is known that, when used for a long period of time, a golf ball absorbs moisture, etc., and that such absorption has a large influence on the quality of the ball, including the initial velocity. For example, a change in weight and a decrease in initial velocity due to absorption are observed in golf balls that use conventional polyurethane covers; such changes have a large effect on the distance traveled by the ball.
U.S. Pat. No. 7,358,320 describes a golf ball that employs in the cover material a polyurea the water vapor transmission of which has been ameliorated by using a fluorine-containing amine. In this golf ball, the water vapor transmission is ameliorated by including fluorine. However, owing to the influence of fluorine, adhesion of the cover to the intermediate layer or core worsens, which may lead to a decline in durability.